Processes Hanging

[William L Stube II]

I am having a problem with processes hanging up after some amount of 
time.  The machine starts up, runs fine for some length of time, then 
httpd processes start hanging around.  All of which appear to be waiting 
for disk.

www      12484  0.0  0.7  3948 2620  ??  D     3:43AM   0:00.02 
/usr/local/sbin/httpd
www      12574  0.0  0.7  3936 2552  ??  D     4:17AM   0:00.01 
/usr/local/sbin/httpd
www      12576  0.0  0.7  3936 2552  ??  D     4:18AM   0:00.01 
/usr/local/sbin/httpd
www      12577  0.0  0.7  3936 2552  ??  D     4:18AM   0:00.01 
/usr/local/sbin/httpd
www      12578  0.0  0.8  4108 2960  ??  D     4:18AM   0:00.03 
/usr/local/sbin/httpd

This time, the processes hung after about 3 days since my last hard 
reset.  The time before that it was about 18 days.  When I attempt to 
reboot the machine just sits there.  I have to power the machine off for 
  it to actually restart.

Any suggestions?

Thanks,

Bill

FreeBSD foo.org 4.8-STABLE FreeBSD 4.8-STABLE #0: Thu Aug  7 09:21:32 
CDT 2003     root at foo.org:/usr/obj/usr/src/sys/molpe48s  i386